This invention relates to transport of different protocol signals.
Increase in communication traffic has generated demand for higher speed and larger throughput in networks. Current core communication networks connecting line concentrators, bases, or providers' networks employ large-throughput transport achieved by data multiplexing. Examples of such large throughput transport include SDH/SONET (Synchronous Digital Hierarchy/Synchronous Optical NETwork) which multiplexes a low-speed signal with a predetermined speed signal and OTN (Optical Transport Network) which has achieved large-throughput transport by employing a concept of optical path suitable for WDM (Wavelength Division Multiplexing) communication.
The foregoing large-throughput transport technologies have a problem that extensive device configuration is required to handle a plurality of signals. In such a circumstance, a technique to achieve synchronous detection of multiple frame rates in the SDH or SONET with a single circuit is disclosed in JP 2003-143097 A. In the meanwhile, JP 2008-227995 A discloses a multi-rate interface board that generates OTN frames from low-speed signals that are not standardized as OTN frames, independently from the type of signal.
In recent years, signals (protocols) used in a network are diversified to meet their usage; for example, the link layer supports various protocols, such as Ethernet™, FibreChannel, and InfiniBand, together.
In such a circumstance, for a network that multiplexes links having different transmission data rates for transport, a multi-rate signal multiplexing technique is increasingly demanded that does not depend on the protocol or transmission data rate.